Blood coagulation is a natural reparative process in which a blood clot is formed in response to blood or blood vessel trauma. Normally, blood contains platelets and other cells, as well as fibrinogen and other molecules, all of which circulate freely in the blood. However, in response to trauma to the blood or blood vessels, and in the absence of pathological or therapeutically induced conditions preventing some aspect of blood coagulation, the platelets agglutinate. As the platelets agglutinate, there is an increase in the concentration of the chemical thrombin in the blood. The thrombin has a proteolytic effect on the fibrinogen molecules circulating in the blood. This proteolytic activity results in the formation of fibrin monomers from the fibrinogen molecules. Then, in proximity to the surface of the agglutinated platelets, the fibrin monomers spontaneously polymerize into fibrin polymers. While the fibrin polymers are initially linked by hydrogen bonds, the fibrin is later stabilized by covalent bonds among the fibrin polymers resulting in a meshwork of fibrin polymers. This meshwork of fibrin polymers comprises the blood clot.
Unfortunately, any of a number of pathological and therapeutically induced conditions can prevent the formation of fibrin polymers. Fibrin polymers may fail to form because of coagulation problems, such as when there is a genetic defect limiting production of one or more required coagulation factors. Fibrin polymers may also fail to form if there is a deficiency of functioning platelets. Platelet concentrations may be deficient due to a failure of platelet production, to excessive platelet destruction or to excessive platelet storage in the spleen. If platelet concentrations are decreased, platelet agglutination will necessarily decrease. A decrease in platelet agglutination can limit the production of fibrin polymers by decreasing the available surface upon which the fibrin monomers can polymerize in the process leading to clot formation. Even if sufficient platelets are present, however, defects in platelet function can prevent the formation of fibrin polymers, such as when platelets do not synthesize or release required chemical reactants.
Of course when platelets and coagulation factors are present in normal concentrations and functioning adequately, fibrinogen must still be present in sufficient concentration if the polymerization of fibrinogen into fibrin is to occur. If there is no fibrinogen, fibrin monomers cannot be formed. In the absence of fibrin monomers, polymerization of fibrin cannot occur. Thus, the concentration of fibrinogen in a particular individual is directly related to that individual's potential for blood coagulation.
It could be helpful if physicians were able to better evaluate or determine a patient's potential for blood coagulation by measuring the patient's blood fibrinogen content. Knowledge of the blood fibrinogen content would allow physicians to more accurately pinpoint or eliminate excessive or inadequate blood fibrinogen levels as the cause of individual coagulation disorders. Furthermore, knowledge of fibrinogen content would also help avoid some surgical complications which might otherwise occur because of an excessive or inadequate concentration of blood fibrinogen of an individual undergoing surgery.
Currently, much detailed information about an individual's blood coagulation characteristics is available to aid physicians in the diagnosis of coagulation disorders and in the prevention of surgical and post-surgical coagulation complications. There are techniques currently available which measure coagulation times, coagulation factors, platelet function, fibrinolytic activity, the presence of circulating inhibitors, as well as other individual blood clotting characteristics. There is, however, no apparatus or method currently known which can rapidly and accurately quantify or evaluate fibrinogen levels.
It is against this background information that the below described significant improvements and advancements have taken place in the field of blood coagulation measurement.